The present invention relates to a receive data processing device and, more particularly, to a receive data processing device installed in a reference ground station of a time division multiple access (TDMA) satellite communications network, which is adapted to monitor and control satellite communications channels, in order to monitor operating conditions of the other ground stations which it covers.
As well known in the art, a TDMA communications system has recently been developed as one of communications systems which are applicable to satellite communications channels of the kind using digital modulation. Details of a TDMA communications system are discussed in OUTLINE OF INTELSAT TDMA/DSI SYSTEM, Study of International Communications, No. 110, pages 53-83, published Oct. 1981 in Japan, and others and, therefore, will not be described herein.
In a TDMA satellite communications system, a communication satellite usually mount therein a transponder having a plurality of transponder channels, while a predetermined number of reference ground stations and a predetermined number of other ground stations which provide a traffic system are distributed each in a predetermined area for the multiple transponder channels. Basically, the TDMA communications system is devised for allowing a repeating function assigned to the transponder to be shared by the ground stations inclusive of the reference stations on a time division basis.
In a TDMA communications system, a time sequence generally referred to as a TDMA frame and extending over 2 milliseconds is divided into a predetermined number of time slots to assign the time slots to ground stations in a network in one-to-one correspondence. Satellite communications channels are set up such that any of the ground stations inclusive of the reference station is capable of using the transponder excluding the others for a predetermined period of time.
A prior art receive data processing device is provided with n (particular positive integer) received data processing sections in correspondence with n satellite transponder channels in order to accommodate n independent TDMA frames or sequences. Each of the receive data processing sections is made up of an elastic buffer, a signal separator for sync control, a terminal monitor circuit, a write control circuit, a read control circuit, etc. It follows that, where n receive burst data sequences come in in correspondence with n transponder channels and all the ground stations are to be monitored, n receive data processing sections are needed in one-to-one correspondence with the receive burst data sequences, resulting in a a receive data processing device having a prohibitive circuit scale.